1. Field of the Invention
The invention is directed to a rotary locking cylinder and, in particular, to a rotary locking cylinder for a safety lock in which spring-loaded pin tumblers are supported in bore holes extending radially relative to a rotor and a cylinder housing and can be brought into line by inserting a key into a key groove to enable the rotation of the rotor.
2. Description of the Related Art
A rotary locking cylinder of this type is known, for example, from EP-B-0 238 442. In break-in attempts, even high-priced rotary locking cylinders of this kind are subject to a wide variety of known and new methods of opening. Some of these methods are non-destructive and incapable of detection. The rotary locking cylinder according to the patent mentioned above foils such methods, e.g. the vibration method, by way of a special a construction of the tumblers. However, there are also methods of unauthorized opening in which the rotary locking cylinder is destroyed by the use of crude force. When attempting to open the lock in this way, for example, rotation of the rotor is forced by inserting a tool into the key groove so that the tumbler pins are sheared off. This forced method of entry is difficult to combat by modifying the rotary locking cylinder, since such changes are restricted by preestablished dimensions. Finally, such a rotary locking cylinder should be simple and inexpensive to manufacture and should operate reliably. A rotary locking cylinder which at least substantially impedes a number of methods of unauthorized opening at the same time would be particularly desirable.